Introduction

by Neetu Jain
(Delhi)

Original Text: Introduction

Despite substantial advances in trauma care, critical traumatic injuries remain one of the leading causes of death in the below 44 years age group 1. Increased mortality in the critically ill adult trauma population is not solely due to the direct effects of trauma. Patients who survive the initial injury acquire nosocomial infections, which are the leading cause of death in them 1, 2. Trauma patients usually have prolonged ICU stay and therefore are more prone to acquire hospital acquired infections (HAIs). These patients are usually treated with broad spectrum antibiotics, making them more prone to acquire Candida infections. In ICUs, the common infections due to Candida sp. are catheter related blood stream infections (CR-BSIs), intra-abdominal infections and urinary tract infections (UTIs). Invasive candidiasis is recognized as a leading cause of morbidity and mortality in both immunocompentent and immunocompromised patients; the crude and attributable mortality may be as high as 40% and 20% respectively 3, 4. Better management of these infections depends on rapid identification and reporting of results. In the past decade, hospitals across the world have witnessed a change in the epidemiology of Candida infection, characterized by a progressive shift from Candida albicans to a predominance of non-albicans Candida Spp. 4, 5, 6. There is growing evidence of the increasing use of azoles causing this epidemiological shift 4, 7. Characterization to species level helps to identify those strains which might be intrinsically resistant to some of the antifungal agents. Identification of yeast pathogens by traditional methods requires several days and specific mycological media. These methods are thus labor and time consuming. Several brands of chromogenic media are available for rapid identification of Candida Spp. The chromogenic media contain substrates which react with enzymes secreted by the target microorganisms to yield colonies of varying colors 8, 9, 10. Commercial automated identification systems have also been developed and are being used in some routine clinical microbiology laboratories. These systems have been reported to allow for accurate and more rapid identification of medically relevant bacteria and yeast 11, 12, 13, 14, 15. The Vitek 2 system (Biomeriux, France) is a fully automated system, dedicated to the identification and susceptibility testing of microorganisms. The ID-YST database of Vitek 2 comprises of 51 different taxa, including newly described species, taking into account recent advances in taxonomy.In this study, we evaluated the performance of a commercially available chromogenic candida speciation media and the Vitek - 2 ID system for the identification of medically important yeasts and yeast like organisms in a routine clinical microbiology laboratory.

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Revised Text:

Despite substantial advances in trauma care, critical traumatic injuries remain one of the leading causes of death in the below 44 years age group 1.

Increased mortality in the critically

ill, adult trauma population is not solely due to the direct effects of trauma. Patients who survive the initial injury acquire nosocomial infections, which are the leading cause of death in them 1, 2. Trauma patients usually have prolonged ICU stay and therefore are more prone to acquire hospital acquired infections (HAIs). These patients are usually treated with broad spectrum antibiotics, making them more prone to acquire Candida infections.

In ICUs, the common infections due to Candida sp., are; catheter related blood stream infections (CR-BSIs), intra-abdominal infections and urinary tract infections (UTIs). Invasive candidiasis is recognized as a leading cause of morbidity and mortality in both immuno-competent and immuno-compromised patients. The crude and attributable mortality may be as high as 40% and 20% respectively 3, 4. Better management of these infections depends on rapid identification and reporting of results.

In the past decade, hospitals across the world have witnessed a change in the epidemiology of Candida infection, characterized by a progressive shift from Candida albicans to a predominance of non-albicans Candida Spp. 4, 5, 6. There is growing evidence of the increasing use of azoles causing this epidemiological shift 4, 7. Characterization to species level helps to identify those strains which might be intrinsically resistant to some of the antifungal agents.

Identification of yeast pathogens by traditional methods requires several days and specific mycological media. These methods are thus labor and time consuming. Several brands of chromogenic media are available for rapid identification of Candida Spp. The chromogenic media contain substrates which react with enzymes secreted by the target microorganisms to yield colonies of varying colors 8, 9, 10.

Commercial, automated identification systems have also been developed and are being used in some routine clinical microbiology laboratories. These systems have been reported to allow for accurate and more rapid identification of medically relevant bacteria and yeast 11, 12, 13, 14, 15.

The Vitek 2 system (Biomeriux, France) is a fully automated system, dedicated to the identification and susceptibility testing of microorganisms. The ID-YST database of Vitek 2 includes 51 different taxa, including newly described species, taking into account recent advances in taxonomy.

In this study, we evaluated the performance of a commercially available chromogenic candida speciation media and the Vitek - 2 ID system for the identification of medically important yeasts, and yeast like organisms, in a routine clinical microbiology laboratory.